[Anatomic and radiological observations of th bifid mandibular condyle]

To determine the morphology and the frequency of bifid mandibular condyle (BMC) in anatomic material and to study its diagnosis in living persons.

The morphology and the frequency of BMC were studied on a sample of 210 intact mandibular condyles belonging to a collection of 200 dry male adult skulls held by the Institute of Anatomy of University of Bologna. Diagnostic imaging was verified retrospectively on 6 cases of BMC observed in living subject.

In the anatomic material, we found 29/210 mandibular condyles with the articular surface simply parted in two (13.80%) and 1 condyle consisting of two separate articular heads (0.47%) at different levels and without the neck. Therefore BMC with separate neck is very rare. In living persons diagnosis was established by radiology using orthopantomography and demonstrated 2 cases of bilateral BMC (one dysplasic and the other traumatic) and 4 of unilateral BMC.

We believe that primitive BMC is a consequence of a dysplasic process of the condyle cartilage at the early stages of its development, while secondary traumatic BMC is caused by bone remodelling after articular trauma or repeated microtraumas from malocclusion. In dysplasic BMC, as evidenced by the observation made on a living subject, a distinction should be made between the complete type in which the accessory articular head is separate from the principal head, at a different level and with its own separate neck, and the other, incomplete types. Orthopantomography, which proved to be a valid diagnostic tool, must be integrated with CT and MR if surgery is planned.